The removal of hair from the human epidermis is commonly accomplished by shaving with a mechanical means such as a razor blade or power shaver designed to be used under wet conditions. Hair removal for the human male is a daily exercise to remove facial hair, and for the human female is a regular, but less frequent exercise generally to remove hair from the body such as the legs and underarms.
There are a number of compositions available to facilitate removing hair from the body with the use of mechanical means. Some compositions perform as a pre-shave, to prepare the hair to be removed; as a during-shave, to lubricate the skin and facilitate shaving; and as an after-shave to condition the skin and add fragrance to the area shaved.
A wide variety of soaps, creams and oils are available to facilitate the shaving process. However, in general they cause discomfort and trauma to the skin. Shaving creams are, by far, the preparation of choice for facilitating the shaving process for lessening the abrasion, irritation, and localized trauma which, to a greater or lesser extent, is associated with hair removal by shaving. Shaving creams are lather-producing, either through the action of a brush or as propelled from an aerosol container. Both are commonly formulated using soap and/or detergents as the lather forming composition. The lather or brushless shaving cream are oil-in water emulsions of the cream type.
Shaving cream is also commonly a lather-forming, soap-based formulation further modified for application with a shaving brush or as a soap-based and/or detergent foam from an aerosol dispenser. Such formulations provide an easy and rapid production of copious lather which is supposed to be resistant to collapse; should hold the hair erect; should provide sufficient lubrication for the razor blade and there should be minimum irritation of the skin.
The treatment of human skin with various compositions has been undertaken for many years with the goal being to keep the skin in a smooth supple condition. Skin has the tendency to dry out when exposed to conditions of low humidity or to extended periods in detergent. These considerations have not been adequately taken into consideration when shaving preparations are proposed.
Shaving lotions have generally been prepared with regard to the hair follicles only so as to prepare the hair for cutting by a razor. Silicone products have been introduced in order that a razor may travel more easily on the skin without nicking. None of the products provide any beneficial features to the skin. In fact, most commercial products contain ingredients which cause denaturization or other harmful effects. Shaving preparations containing detergents or soap products or one of such deleterious products, are commonly utilized today. It is only after the shaving process that any concern is made for conditioning the skin. In many cases even those products cause damage and trauma to the skin.
The damaging effects of sunlight on skin are well documented. Damage from excessive UV exposure can occur by sunbathing as well as routine day-to-day activities in the sunlight. Some scientists estimate that over 70 percent of the damage the sun inflicts on the average person's skin over a lifetime is the result of simply being outdoors or even sitting by a window.
The major short term hazard of prolonged exposure to sunlight is erythema (i.e. sunburn). The 290 to 320 nanometer wavelength ultraviolet radiation range, designated as the "UVB" wavelength range, tends to be the primary cause of erythema. The 320 to 400 nanometer wavelength range, also produces erythema.
In addition to the short term hazard of erythema, there are also long term hazards associated with UV radiation exposure. One of these long term hazards is malignant changes in the skin surface. Numerous epidemiologic studies demonstrate a strong relationship between sunlight exposure and human skin cancer.
Another long term hazard of ultraviolet radiation is premature aging of the skin. This condition is characterized by wrinkling and yellowing of the skin, along with other physical changes such as cracking, telangiectasis (spider vessels), solar keratoses (growths), ecchymoses (subcutaneous hemorrhagic lesions), and loss of elasticity (sagging). The adverse effects associated with exposure to UVA and UVB wavelength radiation are more fully discussed in DeSimone, "Sunscreen and Suntan Products", Handbook of Nonprescription Drugs, 7th Ed., Chapter 26, pp. 499-511 (American Pharmaceutical Association, Washington, D.C.; 1982) and Grove and Forbes, "A Method for Evaluating the Photoprotection Action of Sunscreen Agents Against UV-A Radiation" International Journal of Cosmetic Science, 4, pp. 15-24 (1982); the disclosures of all of which are incorporated herein by reference. Hence, although the immediate effects of ultraviolet radiation may be cosmetically and socially gratifying, the long-term hazards are cumulative and potentially serious.
The fact that these effects are taken seriously by the general public is suggested by considering the market for sun protection products. This market has grown considerably in recent years and many new products are introduced each year. What used to be looked upon as a seasonal business is now continuous. Sun protection compositions are now included in a diversity of personal care products, particularly cosmetic-type products for women, which are worn on a daily basis. The human face is exposed to sun radiation more than any other part of the human body; especially in the case of men. Men are becoming more aware of the necessity to wear sun protection compositions on a daily basis.
To remove hair from the body with a razor blade or power shaver designed to be used in wet conditions, one usually applies a pre-shave composition to the area to prepare the hair as well as lubricate the area to facilitate shaving, cut off the hair, wash off the pre-shave composition, apply an after-shave or skin conditioning composition. A sunscreen composition may at some point be applied to the area shaved.
From the foregoing, it is evident that the requirements of a preferred cream with the necessary properties to facilitate shaving on the one hand but formulated from non-irritating chemicals presents a problem of considerable dimension to those skilled in the art. This is partially due to a misunderstanding of what is necessary to affect a close, comfortable, effective non-irritating shave.
From the foregoing it is also evident that the requirements of a preferred sunscreen with the necessary properties to protect one from the harmful effects of radiation on a daily basis is also necessary.